<template>
  <section class="real-app">
    <input
      type="text"
      class="add-input"
      autofocus="autofocus"
      placeholder="todo?"
      @keyup.enter="addTodo"
    >
    <item
      v-for="todo in filteredTodos"
      :key="todo.id"
      :todo="todo"
      @del="deleteTodo"
    ></item>
    <tabs
      :filter="filter"
      :todos="todos"
      @toggle="toggleFilter"
      @clearAllCompleted="clearAllCompleted"
    />
  </section>
</template>

<script>
import Item from "./item.vue";
import Tabs from "./tabs.vue";
let id = 0; //初始值
export default {
  //3. 定义 todo 数据
  data() {
    return {
      todos: [],
      filter: "all"
    };
  },
  computed: {
    filteredTodos() {
      if (this.filter === "all") {
        return this.todos;
      }
      const filterCompleted = this.filter === "completed";
      return this.todos.filter(todo=>filterCompleted===todo.completed);
    }
  },
  //2. 加入组件
  components: {
    Item,
    Tabs
  },
  methods: {
    addTodo(e) {
      this.todos.unshift({
        id: id++,
        content: e.target.value.trim(), //input 的值
        completed: false //状态默认 false 未结束
      });
    },
    deleteTodo(id) {
      this.todos.splice(
        this.todos.findIndex(todo => todo.id === id),
        1
      );
    },
    toggleFilter(state) {
      this.filter = state
    },
    clearAllCompleted() {
      //重新赋值
      this.todos = this.todos.filter(todo=>!todo.completed);
    }
  }
};
</script>

<style lang="stylus" scoped>
.real-app {
  width: 600px;
  margin: 0 auto;
  box-shadow: 0 0 5px #666;
}

.add-input {
  position: relative;
  margin: 0;
  width: 100%;
  font-size: 24px;
  font-family: inherit;
  font-weight: inherit;
  line-height: 1.4em;
  border: none;
  outline: none;
  color: inherit;
  box-sizing: border-box;
  font-smoothing: antialiased;
  padding: 16px 16px 16px 36px;
  border: none;
  box-shadow: inset 0 -2px 1px rgba(0, 0, 0, 0.03);
}
</style>